This project targets the development of a powerful new approach to examine the pharmacokinetics (PK) and pharmacodynamics (PD) of novel drug candidates. Using a 3D printed fluidic device, cell cultures will be dynamically dosed with therapeutics. The 3D printed device offers substantial improvements over current technology, as it contains porous membranes to allow both dosing and clearance of the drugs. In the initial development phase, 3D colon cancer cell cultures, known as spheroids, will be treated with well-characterized chemotherapies. Molecular changes to the spheroids will be monitored via Matrix Assisted Laser/Desorption Ionization Imaging Mass Spectrometry (MALDI-IMS). As both the drugs and their metabolites have defined masses, the penetration and distribution of these species can be mapped throughout the spheroids with MALDI-IMS. The public health benefits of the project lie in the promise of a powerful new tool to characterize the PK/PD of new drugs in a non-invasive, dynamic in vitro context. This approach will make it possible for researchers to build a coherent picture of the molecular changes that underlie the metabolism of new drugs, thus helping to devise more effective treatments, and improve patient outcomes. The project is constructed around three sets of activities. First, the 3D printed fluidic devices will be designed and optimized to dose the 3D cell cultures. The completed end- user friendly device will enable loading of a test-drug molecule and manipulation of its clearance half-life using a simple gradient-pumping scheme. Second, growth and dosing of the spheroids will be optimized in the 3D printed device. Finally, spheroids will be dosed and imaging via MALDI-IMS in a time course experiment. Data will be analyzed via principal component analysis. As an initial proof-of-concept study, spheroids will first be treated with the well-characterized drug irinotecan. Further studies will expand to more complicated therapeutic cocktails, such as an abbreviated simulation of the clinical regime FOLFIRI.